The invention relates to a fastening assembly especially for panels with cavities, which comprises a bolt having a cone at the lower end thereof and an external thread in the upper region thereof, and a sleeve having an expansible region at its lower end.
Expansible fastening assemblies intended for use in drilled holes in masonry having a conical undercut portion, are known. The positive anchoring of these fastening assemblies is effected as follows: a bolt having a cone at its lower end is hammered into the drilled hole together with a sleeve mounted on the bolt. When the bolt reaches the base of the drilled hole, the expansible region of the sleeve expands over a region of the cone by being hammered part of the way over the cone into the drilled hole. Upon fastening by screwing the object to be fastened at the mouth of the drilled hole, the bolt with the cone is then withdrawn into the sleeve until a form-locking interconnected expansion of the expansible region of the sleeve in the undercut drilled hole has been achieved.
A disadvantage of this type of anchoring of a fastening assembly consists in that, especially between a phase taking place when the sleeve is hammered in completely, and the phase in which it is caused to expand by a nut screwed on the bolt with a rotary screwdriver, there is no means for securing a fastening element against falling out. Such means proves necessary, however, especially in the case of vertical drilled holes in ceilings and so on. In addition, in the case of a fastening element not having been hammered completely into the drilled hole, there is a danger of an anchoring assembly by which the object is to be secured, not resting flush against the wall or ceiling. Finally, in the case of the anchoring of such a fastening assembly in a wall or ceiling area in which there are cavities, there is a danger that the bolt cone will not reach the drilled-hole base and, hence, will turn during the screwing of the nut, and a form-locking expansion in the drilled hole will not be ensured.